"I have significant concerns that this bill will cause serious unintentional consequences that could threaten public safety, health care and individuals' civil rights," Beshear said in a statement. "As written, the bill will undoubtedly lead to costly litigation."

House Bill 279 would allow someone with "sincerely held" religious beliefs to disregard state laws "unless the government proves by clear and convincing evidence that it has a compelling governmental interest in infringing" the person's religious freedom. Gay rights and human rights groups have said the bill could be used to challenge local anti-discrimination laws that protect gays and lesbians in Lexington, Louisville, Covington and Vicco.

The sponsor of House Bill 279, Rep. Bob Damron, D-Nicholasville, said he thinks he'll have the 51 votes required to override the veto if House leaders decide to take a vote. Damron said Beshear, a Democrat, did not ask him or Democratic House leaders to refrain from trying to override the bill during a conversation of more than an hour Friday in the governor's Capitol office.

In a written statement, Senate President Robert Stivers, R-Manchester, said, "The Senate is prepared to override the veto of HB 279 if and when the Speaker moves to do so. As a House bill, that chamber must act on the bill first."

House Speaker Greg Stumbo, D-Prestonsburg, said in a statement that Democratic leaders "will be discussing what action to take with our caucus."

The House passed the bill earlier this month with only seven dissenting votes. The Republican-led Senate passed it 29-6.

Lawmakers return to Frankfort on Monday for the final two days of the legislative session. Damron said there will be enough time to override the veto by midnight Tuesday.

Conservative groups that backed the bill criticized Beshear on Friday.

"It won't be comforting for many Kentuckians to know that the ACLU is now calling the shots in the governor's office," said Martin Cothran, spokesman for The Family Foundation. "Religious people should not have to ask permission from the ACLU and gay rights groups to believe what they believe."

Damron said the concerns of opponents are unfounded. Sixteen states have passed similar laws, but none of those states have seen a flood of lawsuits after the bills were passed, Damron said.

But Beshear said in a news release that HB 279 is "fundamentally different" than related federal and state laws, "mostly because the vague language of HB 279 lends itself to overly broad applications."

He said the bill offers no exceptions for certain state agencies or civil rights laws, or for the protection and safety of the general public.

"Imprecise legal standards lead to unforeseen consequences," Beshear said. "Citizens and governmental entities are entitled to a clear understanding of the boundaries of permissible conduct. This bill, as written, while well intended, is undermined by precarious legal wording."

He said the bill had the potential to weaken local civil rights laws, affect curriculum standards in schools, hamper economic development efforts, hinder public health initiatives and undermine enforcement of drug laws.

Beshear released a list of dozens of groups that either opposed the bill or asked him to veto it. Those groups include the Kentucky Association of Counties, the Kentucky League of Cities, the Kentucky Education Association, the American Civil Liberties Union, a variety of gay rights organizations, sexual assault groups and fair housing groups.

In addition, Louisville Mayor Greg Fischer and the Covington City Council had asked Beshear to veto the bill. Lexington Mayor Jim Gray, who is gay, came under fire from some advocacy groups for not publicly asking Beshear to veto it.

Gay rights groups applauded Beshear on Friday for vetoing the bill.

"Both Republicans and Democrats need to think carefully before deciding to override a veto since the governor and his legal staff has listened to both sides of the argument," said Jordan Palmer, president of the Kentucky Equality Federation. "Gov. Beshear is pushing Kentucky to once again be a leader in civil rights protection for minorities throughout the Commonwealth by not infringing on their city equality ordinances in Covington, Lexington, Louisville and Vicco."